The present invention relates to a method of and a device for transferring stitches on a knitting machine by transfer elements.
In all known methods for transferring of stitches, the needles which hold the stitches to be transferred are advanced so far that the stitches slide over the open latch; or the slide of the needle until they are placed on the needle shaft. There the stitch is spread by a spreading spring, so that subsequently it can be taken by a needle of the opposite needle bed or also by transfer fingers. Such methods are disclosed for example in German patent document DE-OS. 24 43 231 and European patent document EP 0 103 033 A1.
The known methods have the disadvantage that a great needle advance distance is required. The control curves which are needed for this purpose require correspondingly wide knitting cams. Moreover, the wide needle advance stroke leads to a reduction of the production speed of the knitting products. The main disadvantage of the known methods is however that the stitches, before the transfer to a neighboring needle or a transfer finger, are pulled far from the stitch structure and spread out, so that sensitive yarns are used for splitting the stitches. The transferred stitches moreover are increased by the transfer process, so that this is visible in smooth knitting products in the overall knitting pattern and therefore the quality of the knitted product is limited.
Accordingly, it is an object of present invention to provide a method of and a device for transferring stitches, which avoid the disadvantages of the prior art.
More particularly, it is an object of the present invention to provide a method of and a device for transferring of stitches, which avoid a high yarn loading and an increase in production time for producing knitted articles.
In keeping with these objects and with others which will become apparent hereinafter, one feature of present invention resides, briefly stated, in a method of transferring stitches on a knitting machine by means of transferring elements, in which a transfer element is associated with all needles on which stitches must be suspended, wherein in accordance with the present invention the stitches held in the needles and to be transferred are placed by needle advance and return movements on the needle ledge or, in case of slide needles, on the closed needle slide, and subsequently the transfer element is inserted into the stitch and the needle is pulled out of the stitch, so that the stitch is suspended alone on the transfer element and is available for transfer on the same or other needle or on another transfer element.
For placing, the stitches on the ledge or on the slide, needle movements are needed as required in normal stitch forming processes. The further advance of the needle to which the stitch is transferred in accordance with the known methods is no longer needed. In the inventive method the stitch is sufficiently clamped by the needle ledge over the needle slide so that the tip of the transfer element can be introduced into the stitch. However, no additional spreading of the stitch when compared with the conventional, not suspended stitch is carried out, so that also no significant increase of the suspended stitch takes place, which can be seen later in the knitted pattern.
For placing of the stitch, different possibilities are provided. The stitch can be placed by a needle advance and subsequent needle return movement on the closed ledge of the needle. It suffices that the needle is advanced so far that the stitch is located behind the open ledge. The stitch can be placed however also by a needle advance movement on the open ledge of the needle. Both, in the case of the open as well as closed ledge, the stitch is sufficiently clamped, so that the transfer element can be inserted into the stitch.
With the use of the slide needles, the stitch can be placed by a needle advance movement with the open slide and a subsequent needle return movement with the closed slide, over the closed slide.
Similar conditions are provided for the transfer process as during placing of the stitch on the closed ledge of a ledge needle. The inventive method for transferring of stitches can be utilized both on flat knitting machines and also on round knitting machines.
The inventive device for transferring stitches on a knitting machine in accordance With the inventive method has an associated transfer element for all needles on which stitches are suspended, and in accordance with the present invention the transfer element has a tip which is formed by at least one plate spring. With the use of the plate spring tip it is possible to provide insertion into stitches which are clampingly held on the ledges or on the slides. The plate spring is introduced in the thread space and runs between the legs of the stitch.
In accordance with a preferable embodiment of the invention, the transfer element cans have a tip formed by two plate springs. One plate spring is displaceable over the left side and the other plate spring is displaceable over the right side of the needle ledge or the needle slide and is insertable between the stitch legs. With such a design, the tip engages with stitch symmetrically left and right of the needle shaft, and the transfer of the stitch to the transfer element is even more reliable. After the return of the needle from the stitch, the both plate spring elements are compressed and together form the tip of the transfer element.
In a transfer device for a flat knitting machine, the transfer element is supported longitudinally displaceably in at least one sinker arranged over the at least one needle bed of the flat knitting machine. For this purpose the at least one sinker is provided with grooves, in which the transfer elements are longitudinal displaceable. The transfer elements have the same distance from one another as the needles of the at least one needle bed. Thereby it is guaranteed that a transfer element is exactly associated with each needle.
When the at least one needle bed of the flat knitting machine is supported not longitudinally displaceably, the at least one sinker is supported longitudinally displaceably on the knitting machine. Thereby a lateral offset of the stitches through the transferring process is possible With the longitudinally displaceable needle beds, the sinker with the transfer elements can be also arranged fixedly.
With a multi-bed knitting machine it is advantageous when for each needle bed of the flat knitting machine at least one sinker with transfer elements is provided. The sinker can be provided over its whole length with transfer elements, or only in its partial regions. Moreover, it is naturally possible, to provide for each needle bed several sinkers in such regions, in which the transfer process must be carried out.
The transfer elements can be controllable preferably similarly as the needles of the flat. knitting machine, in particular by control curves or cams, in which projections arranged on the transfer elements engage. It is advantageous when these control curves are arranged on the slide or slides for needle control of the flat knitting machine. Again, no separate drive for selection of the transfer elements is needed.
The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.